This invention relates to a magnetic recording/reproducing apparatus such as a linear tape storage system represented by DLT (Digital Linear Tape) or LTO (Linear Tape Open) and, in particular, to a loading mechanism for transmitting driving force of a supply reel motor to a reel hub of a tape cartridge.
A linear tape storage system of the type has been developed as a backup for a computer system. A variety of linear tape storage systems have heretofore been proposed. For example, a digital linear tape drive as the DLT is disclosed in U.S. Pat. No. 5,862,014.
The digital linear tape drive (hereinafter may simply be called the xe2x80x9cdrivexe2x80x9d or the xe2x80x9ctape drivexe2x80x9d) is adapted to receive a tape cartridge (hereinafter may simply be called the xe2x80x9ccartridgexe2x80x9d) having a single reel (supply reel). The digital linear tape drive includes a take-up reel in the interior thereof. When the tape cartridge is received in the drive, a magnetic tape is pulled out from the tape cartridge to be wound up around the take-up reel through a head guide assembly (HGA). The head guide assembly serves to guide to a magnetic head the magnetic tape (hereinafter may simply be called xe2x80x9ctapexe2x80x9d) pulled out from the tape cartridge. The magnetic head exchanges information to and from the tape. Typically, the head guide assembly comprises an aluminum plate having a boomerang-like shape and a plurality of large guide rollers, six in number, comprising bearings.
The head guide assembly is also called a tape guide assembly which is disclosed, for example, in U.S. Pat. No. 5,414,585. An example of the guide roller is disclosed in Japanese Unexamined Patent Publication No. 2000-100025 (JP 2000-100025 A).
As disclosed in U.S. Pat. No. 5,793,574 for example, a tape drive typically comprises a generally rectangular housing having a common base. The base has two spindle motors (reel motors). The first spindle motor (reel motor) has a permanently mounted spool (take-up reel) permanently mounted to the base and dimensioned to accept a magnetic tape streaming at a relatively high speed. The second spindle motor (reel motor) is adapted to receive a removable tape cartridge. The first spindle motor (reel motor) is called a take-up reel motor while the second spindle motor (reel motor) is called a supply reel motor. The removable tape cartridge is manually or automatically inserted into the drive via a slot formed on a housing of the drive. When the tape cartridge is inserted into the slot, the cartridge is engaged with the second spindle motor (reel motor). Prior to rotation of the first and the second spindle motors (reel motors), the tape cartridge is connected to the permanently mounted spool (take-up reel) by means of a mechanical buckling mechanism. A number of rollers (guide rollers) are positioned between the tape cartridge and the permanently mounted spool and guide the magnetic tape as it streams at a relatively high speed back and forth between the tape cartridge and the permanently mounted spool.
The digital linear tape drive of the above-mentioned structure requires a pulling device for pulling the tape from the supply reel to the take-up reel. Such pulling device is disclosed, for example, in International Publication No. WO86/07471. According to the disclosure in the publication, the take-up reel is provided with take-up leader means (first tape leader) coupled thereto. To the tape on the supply reel, supply leader means (second tape leader) is fixed. The first tape leader has a tab formed at its one end. The second tape leader has a locking hole. The tab is engaged with the locking hole.
Furthermore, a mechanism for joining the first tape leader to the second tape leader is required. Such joining mechanism is disclosed, for example, in International Publication No. WO86/07295.
Japanese Unexamined Patent Publication No.2000-100116 (JP 2000-100116 A) discloses xe2x80x9cStructure of Leader Tape Engaging Partxe2x80x9d capable of locking an end of a leader tape (second tape leader) to a tape end hooking part of the tape cartridge without requiring a tab protruding on a lateral side of the leader tape.
U.S. Pat. No. 5,857,634 discloses a lock system for preventing the rotation of the take-up reel of the tape drive when the tape cartridge is not inserted into the drive.
The tape drive further comprises a tape head actuator assembly. The tape head actuator assembly is positioned between the take-up reel or spool and the tape cartridge along a tape path defined by a plurality of rollers. During operation, the magnetic tape streams back and forth between the take-up reel or spool and the tape cartridge, coming into close proximity to the head actuator assembly while streaming along the defined tape path. An example of the head actuator assembly is disclosed in U.S. Pat. No. 5,793,574 mentioned above.
On the other hand, Japanese Unexamined Patent Publication No. 2000-149491 (JP 2000-149491 A) discloses an example of the tape cartridge to be received in the digital linear tape drive.
U.S. Pat. No. 6,241,171 discloses a xe2x80x9ctape drivexe2x80x9d in which a tape leader is urged from a tape cartridge to a take-up reel without using a buckling mechanism or a take-up leader.
As described above, the tape drive comprises the first and the second reel motors (i.e., the take-up reel motor and the supply reel motor). The first and the second reel motors are mounted on a chassis (more specifically, on a back surface of the chassis). As the first and the second reel motors, use is typically made of inner-rotor motors. After the tape cartridge containing the supply reel is inserted into the slot of the tape drive, the supply reel must be engaged with the supply reel motor in order to rotate the supply reel. Such engaging operation is called xe2x80x9cloadingxe2x80x9d in this field of the art. A mechanism for engaging the supply reel with the supply reel motor is called a xe2x80x9cloading mechanismxe2x80x9d. More in detail, a rotation driving surface (reel hub) of the supply reel is exposed out from a bottom surface of the tape cartridge, as disclosed in Japanese Unexamined Patent Publication No. 2000-149491 mentioned above. On the other hand, as will later be described in detail, the loading mechanism comprises a drive gear attached to a rotation shaft of a rotor of the supply reel motor to be movable up and down. When the tape cartridge is inserted into the slot of the tape drive, the loading mechanism is activated so that the drive gear is moved upward from the lower surface of the chassis. As a consequence, the drive gear is engaged with the reel hub of the cartridge so that the supply reel can be rotated by the supply reel motor.
Now referring to FIGS. 1 through 7, an existing loading mechanism will be described.
At first referring to FIGS. 2 through 4, description will be made of an existing magnetic recording/reproducing apparatus 10xe2x80x2 comprising the existing loading mechanism.
The magnetic recording/reproducing apparatus 10xe2x80x2 includes a chassis 20xe2x80x2 having an upper surface (front surface) 20xe2x80x2U and a lower surface (back surface) 20xe2x80x2L. The chassis 20xe2x80x2 comprises a diecast of a non-magnetic aluminum material. The upper surface 20xe2x80x2U is divided into first and second upper regions 20xe2x80x2U1 and 20xe2x80x2U2. Similarly, the lower surface 20xe2x80x2L is divided into first and second lower regions 20xe2x80x2L1 and 20xe2x80x2L2 faced to the first and the second upper regions 20xe2x80x2U1 and 20xe2x80x2U2, respectively. The chassis 20xe2x80x2 is provided with first and second openings 20xe2x80x2a1 and 20xe2x80x2a2 formed in the first and the second upper regions 20xe2x80x2U1 and 20xe2x80x2U2 (the first and the second lower regions 20xe2x80x2L1 and 20xe2x80x2L2), respectively. The first opening 20xe2x80x2a1 has a cylindrical shape formed by bending a part of the first upper region 20xe2x80x2U1 downward. Similarly, the second opening 20xe2x80x2a2 has a cylindrical shape formed by bending a part of the second upper region 20xe2x80x2U2 downward.
The magnetic recording/reproducing apparatus 10xe2x80x2 further comprises a take-up reel 30, a first reel motor 40xe2x80x2, a slot portion 50, and a second reel motor 60. The first and the second reel motors 40xe2x80x2 and 60 may be called a take-up reel motor and a supply reel motor, respectively.
The take-up reel 30 is rotatably mounted to the chassis 20xe2x80x2 on the first upper region 20xe2x80x2U1. The first reel motor (take-up reel motor) 40xe2x80x2 is fitted into the first opening 20xe2x80x2a to be attached to the chassis 20xe2x80x2 in the first lower region 20xe2x80x2L2. The first reel motor 40xe2x80x2 serves to rotate the take-up reel 30. The first reel motor 40xe2x80x2 comprises a first motor substrate 41xe2x80x2 made of a magnetic material, a first rotor 42xe2x80x2 rotatably attached onto the first motor substrate 41xe2x80x2, and a first stator 43xe2x80x2 fixedly mounted on the first motor substrate 41xe2x80x2. The first reel motor 40xe2x80x2 is of an inner-rotor type such that the first rotor 42xe2x80x2 is disposed inside. The first rotor 42xe2x80x2 has a first magnet 421xe2x80x2.
On the other hand, the slot portion 50 is formed on the second upper region 20xe2x80x2U2 of the chassis 20xe2x80x2. The slot portion 50 is adapted to receive a tape cartridge (not shown) comprising a rotatable supply reel (not shown). The second reel motor (supply reel motor) 60 is fitted into the second opening 20xe2x80x2a2 to be attached to the chassis 20xe2x80x2 in the second lower region 20xe2x80x2L2. The second reel motor 60 serves to rotate the supply reel when the cartridge is inserted into the slot portion 50. The second reel motor 60 comprises a second motor substrate 61 made of a magnetic material, a second rotor 62 rotatably attached onto the second motor substrate 61, and a second stator 63 fixedly mounted on the second motor substrate 61. Like the first reel motor 40xe2x80x2, the second reel motor 60 is of an inner-rotor type such that the second rotor 62 is disposed inside. The second rotor 62 has a second magnet 621.
As seen from FIGS. 2 and 4, the first reel motor (take-up reel motor) 40xe2x80x2 is arranged in a reversed position with respect to the second reel motor (supply reel motor) 60. In other words, in the first reel motor 40xe2x80x2, the first rotor 42xe2x80x2 and the first stator 43xe2x80x2 are arranged on the lower surface of the first motor substrate 41xe2x80x2. On the other hand, in the second reel motor 60, the second rotor 62 and the second stator 63 are arranged on the upper surface of the second motor substrate 61. Thus, in the second reel motor 60, the second magnet 621 of the second rotor 62 is exposed. Since the second magnet 621 has strong magnetism, the second reel motor 60 is covered with a plate 70 made of an iron-based magnetic material in order to shield magnetic leakage. The plate 70 may be called a floor receiver.
In the magnetic recording/reproducing apparatus 10xe2x80x2 of the above-mentioned structure, a magnetic head 80 carries out information exchange upon a magnetic tape (not shown) pulled out from the supply reel and wound up around the take-up reel 30.
Next referring to FIGS. 1, 5, and 6, the existing loading mechanism 100xe2x80x2 will be described. The loading mechanism 100xe2x80x2 is arranged in the second opening 20xe2x80x2a2 between the supply reel motor 60 and the floor receiver 70. In other words, the loading mechanism 100xe2x80x2 is arranged at the side of the lower surface 20xe2x80x2L (in the second lower region 20xe2x80x2L2) of the chassis 20xe2x80x2.
The supply reel motor 60 has a rotation shaft 611 fixed to the second motor substrate 61 and standing up from an approximate center thereof. The rotation shaft 611 rotatably supports the second rotor 62 through a ball bearing 612. Specifically, the second rotor 62 comprises a cylindrical rotary member 622 attached to the ball bearing 612, a dish-shaped rotary member 623 extending from a lower end of the cylindrical rotary member 622 in a direction perpendicular to an extending direction of the rotary shaft 611 and having an outer peripheral end perpendicularly bent upward, and the second magnet 621 having a ring shape and fixedly attached to an outer peripheral surface of the outer peripheral end of the dish-shaped rotary member 623.
On the other hand, the second stator 63 is disposed on the second motor substrate 61 in close proximity to an outer periphery of the second magnet 621. As illustrated in FIG. 2, the second stator 63 comprises a plurality of stator cores radially extending outward and a plurality of stator coils wound around the stator cores, respectively.
As seen from FIG. 3, the loading mechanism 100xe2x80x2 has a drive hub 110 fixed to an upper end of the cylindrical rotary member 622 of the second rotor 62 by three screws 101. The drive hub 110 has a generally annular shape and has an outer peripheral end bent downward. Specifically, the drive hub 110 has a ring-shaped portion 111 extending in parallel to the second motor substrate 61 and fixed to the upper end of the cylindrical rotary member 622, and a cylindrical portion 112 perpendicularly bent downward from an outer peripheral end of the ring-shaped portion 111. The cylindrical portion 112 is provided with three grooves 112a (only one being illustrated in FIG. 1) formed on its outer peripheral wall to extend in a vertical direction (i.e., a direction along which the rotary shaft 611 extends) at an angular interval of 120xc2x0. The cylindrical portion 112 has three engaging holes 112 (two of them being illustrated in FIG. 1) formed at its lower end between every adjacent ones of the three grooves 112a at an angular interval of 120xc2x0.
Around the drive hub 110, a drive gear 120 is arranged. The drive gear 120 has a generally double-cylinder shape. Specifically, the drive gear 120 comprises an inner cylindrical portion 121, an outer cylindrical portion 122 spaced from the inner cylindrical portion 121 at a predetermined distance, and a ring-shaped portion 123 connecting the inner and the outer cylindrical portions 121 and 122 at their upper ends. Therefore, the drive gear 120 has a cylindrical groove 120a formed between the inner and the outer cylindrical portions 121 and 122. When the drive gear 120 is moved upward as illustrated in FIG. 6, the cylindrical portion 123 is engaged with a reel hub of the cartridge. In the cylindrical groove 120a, a spring 130 is disposed. The spring 130 continuously urges the drive gear 120 upward. The inner cylindrical portion 121 has an inner peripheral wall provided with three rod-like protrusions 121a (only one being illustrated in FIG. 1) inserted into the three grooves 112a of the drive hub 110 and extending in the vertical direction. The drive gear 120 further comprises an inner ring-shaped flange 124 formed at a lower end of the inner cylindrical portion 121 to protrude inward, and an outer ring-shaped flange 125 formed at a lower end of the outer cylindrical portion 122 to protrude outward. The inner ring-shaped flange 124 is provided with three engaging protrusions 124a (only one being illustrated in FIG. 1) formed at its upper end at positions corresponding to the three engaging holes 112b of the drive hub 110. Thus, when the drive gear 120 is moved upward as illustrated in FIG. 6, the three engaging protrusions 124a and the three engaging holes 112b of the drive hub 110 are engaged with each other.
When the loading mechanism 100xe2x80x2 is not operated, the drive gear 120 is received in the second opening 20xe2x80x2a2 as illustrated in FIG. 5. When the loading mechanism 100xe2x80x2 is operated, the drive gear 120 protrudes upward from the lower surface 20xe2x80x2L of the chassis 20xe2x80x2 as illustrated in FIG. 6. Thus, the loading mechanism 100xe2x80x2 has an elevation control mechanism (which will later be described in detail) for controlling an elevating movement of the drive bear 120. Briefly speaking, when the loading mechanism 100xe2x80x2 is not operated, the elevation control mechanism carries out control so that the drive gear 120 is located at a lower level against the urging force of the spring 130 and received in the second opening 20xe2x80x2a2 as illustrated in FIG. 5. On the other hand, when the loading mechanism 100xe2x80x2 is operated, the elevation control mechanism carries out control so that the drive gear 120 is located at a higher level utilizing the urging force of the spring 130 as illustrated in FIG. 6.
Next, description will be made in detail about the existing elevation control mechanism used in the existing loading mechanism 100xe2x80x2.
The existing elevation control mechanism comprises a ring cam 140xe2x80x2 which is arranged to be rotatable around the rotary shaft 611 and which covers the second stator 63 of the supply reel motor 60, the second magnet 621 of the second rotor 62, and the outer peripheral end of the dish-shaped rotary member 623. More in detail, the ring cam 140xe2x80x2 comprises a ring-shaped member 141xe2x80x2 covering the second stator 63, the second magnet 621, and the outer peripheral end of the dish-shaped rotary member 623 and spaced at a predetermined distance from upper surfaces thereof, an inner cylindrical member 142xe2x80x2 perpendicularly bent downward from an inner peripheral edge of the ring-shaped member 141xe2x80x2 and spaced at a predetermined distance from an inner peripheral end of the second stator 63, and an outer cylindrical member 143xe2x80x2 perpendicularly bent downward from an outer peripheral edge of the ring-shaped member 141xe2x80x2 and spaced at a predetermined distance from an outer peripheral end of the second stator 63. The outer cylindrical member 143xe2x80x2 is provided with a gear portion 140xe2x80x2a formed at a part thereof to be engaged with a gear (not shown). As illustrated in FIG. 1, the inner cylindrical member 142xe2x80x2 is provided with three cam grooves 142xe2x80x2a (only one being illustrated in FIG. 1) formed on an inner peripheral wall thereof to obliquely extend from its lower end towards its upper end. The three cam grooves 142xe2x80x2a are arranged at an angular interval of 120xc2x0 to be rotationally symmetrical with respect to the rotary shaft 611.
On the inner peripheral wall of the inner cylindrical member 142xe2x80x2 of the ring cam 140xe2x80x2, a cylindrical ring cam pivot 150xe2x80x2 is disposed. The ring cam pivot 150xe2x80x2 is provided with a flange 151xe2x80x2 formed at its lower end to extend outward in a radial direction. The flange 151xe2x80x2 is brought into contact with the lower end of the inner cylindrical member 142xe2x80x2. The ring cam pivot 150xe2x80x2 is provided with three long holes or guide slits 150xe2x80x2a (two of them being illustrated in FIG. 1) formed at an equiangular interval of 120xc2x0 to extend in the vertical direction in parallel to the rotary shaft 611.
A drive ring 160xe2x80x2 is arranged to be movable vertically (up and down) in sliding contact with an inner peripheral wall of the ring cam pivot 150xe2x80x2. The drive ring 160xe2x80x2 is provided with three through holes 160xe2x80x2a (two of them being illustrated in FIG. 1) formed at positions corresponding to the three guide slits 150xe2x80x2a and extending in the radial direction at an equiangular interval of 120xc2x0. From the outside in the radial direction, three rod-like engaging pins 161xe2x80x2 are fitted into the three through holes 160xe2x80x2a through the three guide slits 150axe2x80x2 of the ring cam pivot 150xe2x80x2. The three engaging pins 161xe2x80x2 have radially outward ends engaged with the three cam grooves 142xe2x80x2a formed on the inner cylindrical member 142xe2x80x2 of the ring cam 140xe2x80x2, respectively.
When the drive gear 120 is received in the second opening 20xe2x80x2a2 as illustrated in FIG. 5, the three engaging pins 161xe2x80x2 are located at lower ends of the three cam grooves 142xe2x80x2a. On the other hand, when the drive gear 120 is operated as illustrated in FIG. 6, the three engaging pins 161xe2x80x2 are located at upper ends of the three cam grooves 142xe2x80x2a. 
The drive ring 160xe2x80x2 has an inner peripheral wall provided with a protruding portion 162xe2x80x2 protruding inward from its upper part. The protruding portion 162xe2x80x2 is engaged with the outer ring-shaped flange 125 of the drive gear 120. Thus, it will be understood that the position of the drive gear 120 is restricted by the position of the drive ring 160xe2x80x2.
As illustrated in FIG. 5 or 6, an upper surface of the ring-shaped member 141xe2x80x2 of the ring cam 140xe2x80x2 is covered with the floor receiver 70.
In the existing loading mechanism 100xe2x80x2 described above, the drive ring 160xe2x80x2 is formed in the following manner. A disc-shaped plate of aluminum is prepared and subjected to a cutting process to form an opening at the center of the plate. As a consequence, a ring-shaped member is obtained. Then, three through holes 160xe2x80x2a are formed in the ring-shaped member to obtain the drive ring 160xe2x80x2. Thus, production of the drive ring 160xe2x80x2 inevitably requires a long time and is accompanied with generation of a large amount of cutting dust.
It is therefore an object of this invention to provide a loading mechanism capable of considerably reducing a production cost by the use of a drive ring comprising a press formed product.
According to this invention, there is provided a loading mechanism for use in a tape drive comprising a supply reel motor for driving a supply reel in a tape cartridge. The loading mechanism is for engaging a rotor of the supply reel motor with the supply reel. The loading mechanism comprises a drive hub fixed to the rotor, a drive gear arranged coaxially with the rotor to be movable in an axial direction, the drive gear being engaged with the drive hub and the supply reel in a rotating direction when the drive gear is moved towards one direction in the axial direction, a spring urging the drive gear towards the one direction in the axial direction, and a control mechanism for controlling the movement of the drive gear in the axial direction. The control mechanism comprises a ring cam arranged coaxially with the rotor to be rotatable and having a cam groove formed on its peripheral surface, a cylindrical member arranged coaxially with the rotor and having a guide slit extending in the axial direction, a drive ring arranged coaxially with the rotor to be movable in the axial direction and engaged with the drive gear against urging force of the spring, the drive ring being formed by pressing a ring-shaped plate material, and an engaging pin fixed to the drive ring and engaged through the guide slit with the cam groove.